Air cleaner having anti-rotational arrangements and methods

ABSTRACT

An air cleaner having a housing body and a removable cover and a filter element, in which the cover and the filter element rotationally interfere with each other by engagement between an inside surface of the cover and an outer radial periphery of the filter element. A filter element includes a pair of end caps, filter media, and an outer wall on the end cap circumscribing the filter media, in which the outer wall is non-circular. A method of installing a filter element into a housing includes orienting a cover over an element and a housing body by engaging an inside surface of the cover and an outer radial periphery of the filter element to rotationally interfere with each other.

This application is a Continuation of U.S. application Ser. No.13/439,261 filed on Apr. 4, 2012, issued as U.S. Pat. No. 8,444,735;application Ser. No. 13/439,261 is a continuation of U.S. applicationSer. No. 12/063,702, filed on 21 Jul. 2008 and issued as U.S. Pat. No.8,163,056; application Ser. No. 12/063,702 is a National Stage of PCTInternational Application No. PCT/US2006/031812, filed on 15 Aug. 2006in the name of Donaldson Company, Inc., a U.S. national corporation,applicant for the designation of all countries except the US, and PaulR. Coulonvaux, Johan G. DeWit, and Tom H G Vranken, all citizens ofBelgium, applicants for the designation of the US only, and claimspriority to European Patent Application No. 05107531.5, filed 16 Aug.2005.

TECHNICAL FIELD

This application relates to air cleaners, including housings and filterelements. In particular, this application relates to air cleaners foruse in filtering intake air for engines.

BACKGROUND

In general, the machinery, vehicles, or other equipment that operatewith internal combustion engines require filtration systems for airintake to the engine. Such air filtration arrangements, typicallyreferenced by the term “air cleaner”, are generally positioned toseparate dust and other components from the air as it is drawn into theengine. Air cleaners typically include a housing and a replacementfilter element arrangement. Typically, the air cleaners are designedsuch that the filter elements can be removed and replaced. Aircompressor systems typically include two air lines that need filtration:the intake air to the engine, and the intake air to the compressed airstorage. Air cleaners are desirable for these systems as well.

Sometimes, in certain environments, air cleaners are in environmentsthat subject them to substantial vibration. For example, if the aircleaner is used for an over-the-highway truck, the contact between thetruck and the road can cause vibration. Vibration can be even moreexacerbated in off-road vehicles. A combination of factors cancontribute to vibration on the air cleaner.

When there is vibration, the filter element may move within the aircleaner housing. Sometimes, the filter element can rotate within thehousing. The filter element moving within the housing is undesirablebecause it may cause the seal between the filter element and the housingto be released or otherwise compromised. An air cleaner to address thisproblem is needed.

SUMMARY

In one aspect, a filter element is provided that has structure toprevent rotation of the filter element when installed in a housing. Inone embodiment, the filter element has first and second end caps, withthe second end cap including an outer wall circumscribing a tubularextension of filter media, and the outer wall is non-circular.

In certain preferred embodiments, the outer wall defines at least oneapex. In some embodiments, the outer wall defines a plurality of apices.In some embodiments, the outer wall is polygon-shaped. Furthermore, insome embodiments, the outer wall has the shape of a regular polygon.

In one embodiment, the outer wall has a first section and a secondsection extending from the first section, with the first section havingthe non-circular shape. The second section has a circular shape.

In some embodiments, the second end cap includes an axial portion havinga central region with a closed recess projecting into an open filterinterior and a projection extending axially from the central region.

In another aspect, an air cleaner is provided. The air cleaner includesa housing body and a removable cover, and a filter element is operablymounted in the housing body. The cover and the filter elementrotationally interfere with each other by engagement between an insidesurface of the cover and an outer radial periphery of the filterelement.

In one embodiment, the outer radial periphery of the filter element isnon-circular, and the inside surface of the cover is non-circular.

In one embodiment, the filter element has first and second end caps withthe first end cap having an opening and a sealing portion extendingradially into the opening to form a radial seal with the housing body.

In one embodiment, the outer wall of a second end cap defines aplurality of apices, and the cover inside surface defines a plurality ofapices. In some embodiments, the outer wall of the end cap defines aregular polygon, and the cover inside surface defines a regular polygon.

In one embodiment, the second end cap includes an axial portion having acentral region with a closed recess projecting into an open filterinterior, and a projection extending axially from the central region.The cover includes a protrusion projecting into the closed recess of thesecond end cap. In one embodiment, the cover defines a recess orientedto receive the projection of the second end cap.

In some embodiments, the air cleaner further includes a safety elementoriented in an interior of the filter element.

In another aspect, a method of installing a filter element into ahousing is provided. The method includes operably orienting the filterelement into a housing body and orienting a cover over the element andthe housing body. The step of orienting a cover over the element and thehousing body includes engaging an inside surface of the cover and anouter radial periphery of the filter element to rotationally interferewith each other.

In some embodiments, the step of engaging the cover inside surface andthe filter element outer radial periphery to rotationally interfere witheach other includes engaging an end cap on the filter element having anouter wall with a regular polygon shape against the cover insidesurface, and the cover inside surface also has a regular, polygon shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of an air cleaner including ahousing and a filter element, constructed according to principles ofthis disclosure;

FIG. 2 is an end elevational view of the air cleaner of FIG. 1 in anassembled orientation;

FIG. 3 is a cross-sectional view of the air cleaner depicted in FIG. 1,the cross-section being taken along the line 3-3 of FIG. 2;

FIG. 4 is an enlarged cross-sectional view depicting the interfacebetween the filter element and the housing cover, the cross-sectionbeing taken along the line 4-4 of FIG. 3;

FIG. 5 is an end elevational view of the filter element used in thefilter assembly of FIG. 1;

FIG. 6 is a cross-sectional view of the filter element depicted in FIG.5, the cross-section being taken along the line 6-6 of FIG. 5;

FIG. 7 is an enlarged cross-sectional view of the second end cap of thefilter element depicted in FIG. 6;

FIG. 8 is an enlarged cross-sectional view of the first end cap depictedin FIG. 6;

FIG. 9 is a side elevational view of the housing cover used in theassembly of FIG. 1;

FIG. 10 is a schematic, partial side-elevational view of a secondembodiment of a filter element installed in a housing cover;

FIG. 11 is a schematic, cross-sectional view of the element installed inthe cover, the cross-section being taken along the line 11-11 of FIG.10;

FIG. 12 is a schematic, cross-sectional view showing the interfacebetween the filter element and housing cover, the cross-section beingtaken along the line 12-12 of FIG. 10;

FIG. 13 is an enlarged cross-sectional view of a portion of theinterface between the filter element and the housing cover taken atsection 13-13 of FIG. 12;

FIG. 14 is an end elevational view, with a portion broken away, of thefilter element depicted in FIG. 10;

FIG. 15 is an enlarged cross-sectional view of a portion of the filterelement, the cross-section being taken along the section 15-15 of FIG.14;

FIG. 16 is a cross-sectional view of the cover depicted in FIG. 10; and

FIG. 17 is a cross-sectional view of a portion of the cover of FIG. 16,the cross-section being taken along the line 17-17 of FIG. 16.

DETAILED DESCRIPTION

In FIG. 1, an air cleaner 10 is shown in exploded view. The air cleaner10 depicted includes a housing 12 and a removable and replaceable filterelement 14. In the one shown, the housing 12 includes a housing body 16and a removable service cover 18. The cover 18 provides for serviceaccess to an interior of the housing body 16 for servicing. For an aircleaner 10 of the general type depicted in FIG. 1, servicing generallyinvolves dismounting and removing from the housing 12 at least onefilter element, such as filter element 14 depicted, either forrefurbishing or replacement.

The housing 12 depicted includes an outer wall 20, an air inlet 22, andan air outlet 24. For the embodiment depicted, the inlet 22 and theoutlet 24 are both in the housing body 16. In other embodiments, atleast one of the inlet 22 or outlet 24 can be part of the cover 18. Intypical use, ambient or unfiltered air enters the air cleaner 10 throughthe inlet 22. Within the air cleaner 10, the air is passed through thefilter element 14 to obtain a desirable level of particulate removal.The filtered air then passes outwardly from the air cleaner 10 throughthe outlet 24 and is directed by appropriate duct work or conduits to aninlet of an air intake for an associated engine, or compressor, or othersystem.

The particular air cleaner 10 depicted has outer wall 20 defining abarrel shape or generally cylindrical configuration. In this particularconfiguration, the outlet 24 can be described as an axial outlet becauseit generally extends in the direction of and circumscribes alongitudinal central axis defined by the filter element 14.

The service cover 18 generally fits over an open end 26 of the housingbody 16. In the particular arrangement shown, the cover 18 is secured inplace over the end 26 by latches 28. FIG. 9 depicts a side elevationalview of one embodiment of the service cover 18, including the latches28.

In FIG. 3, a partial cross-sectional view of the air cleaner 10 isdepicted. In reference now to FIG. 3, it can be seen that the body 16defines an interior 30 of the air cleaner 10. Within the interior 30 forthe particular air cleaner 10 depicted is positioned the filter element14, through which air is directed during use. In this embodiment, thereis also depicted an optional secondary or safety filter element 32.

Herein, the terms “filter element” or “element” refer to a removable,replaceable component that includes filter media through which the airbeing filtered passes, as the air is directed, from the inlet 22,through the interior 30, to the outlet 24, with the element 14performing an air filtration (or dust removal) function. Unlessotherwise stated, the terms “element”, “filter element”, and “filter”are meant to refer to a removable and replaceable component within theair cleaner 10. Preferably, filter elements are configured such thatthey can be removed and replaced by hand, at appropriate serviceintervals.

Herein, the term “primary element” generally refers to a filter elementin which a majority of dust loading occurs during air cleaner use. Intypical systems that have two elements, the primary element ispositioned upstream from the safety element, during typical assembly. By“upstream” in this context, it is meant that due to filter elementposition, air cleaner configuration, and the location of seals duringuse, air generally must pass through the primary element before the airpasses through the safety element when the air moves from the inlet 22to the outlet 24.

Herein, the term “safety element” refers to a downstream element fromthe primary element. Typically, very little dust loading occurs on thesafety element and generally occurs only as a result of either failureof some portion of the primary element or failure of a seal, orinadvertent dust movement during servicing of the primary element, orsome other mishap.

The safety element 32 depicted in FIG. 3 includes a cylindricalextension of filter media 34 defining an open filter interior 36. Thefilter media 34 extends between an open end cap 38 and a closed end cap40. The filter media 34 used in the safety element 32 can be pleatedmedia, depth media, felt, or any type of media as determined appropriateby the designer of the air cleaner 10.

The safety element 32 is operably installed within the housing 12 toallow it to be sealed and occasionally removed and replaced with a newsafety element 32. A seal 42 is depicted between the safety element 32and the housing 12. While a number of different type of seals could beused, in the embodiment shown, the seal 42 depicted is a radial seal 44;specifically, an outwardly directed radial seal between the open end cap38 and an internal wall 46 of the body 16.

In the embodiment shown, the closed end cap 40 of the safety element 32is generally a flat disk 48. In some embodiments, the closed end cap 40can include a projection that engages a portion of the primary element14. An example of the engagement between the safety element 32 and theprimary element 14 is shown in U.S. Pat. No. 6,652,614, incorporated byreference herein.

In reference now to FIGS. 5-8, the filter element 14 is described infurther detail. FIG. 5 shows an end view of the filter element 14 at itsclosed end. The element 14 depicted has closed end 50 and an open end 52(FIG. 6). In the embodiment shown, the open end 52 is defined by a firstend cap 54, while in the embodiment shown, the closed end 50 is definedby a second end cap 56. FIG. 5 also depicts ornamentation 57 to provideeye-catching, attractive qualities to the element 14. The particularornamentation 57 is also distinctive to the patent assignee, DonaldsonCompany.

Extending between the first end cap 54 and second end cap 56 is atubular extension of filter media 58. In the embodiment shown, thetubular extension of filter media 58 is cylindrical in shape, and inother embodiments, could be conical or oval, for example. The tubularextension of filter media 58 defines an open filter interior 60. In theembodiment shown in FIG. 3, the open filter interior 60 accommodates thesafety element 32. Many different types of filter media 58 can be used.In the embodiment shown, the filter media 58 is depicted as pleatedmedia 62. The pleated media 62 can be pleated paper or cellulose.

In the embodiment shown in FIG. 6, also extending between the first endcap 54 and second end cap 56 is an inner media support or liner 64. Theinner liner 64 helps to support the media 58 due to operating pressuresand other conditions. The inner liner 64 can be non-metal, or it mayalso be metal, such as an expanded metal.

In the particular embodiment shown in FIG. 6, also depicted extendingbetween the first end cap and second end cap 56 is an outer filtersupport or outer liner 66. The outer liner 66 helps to support thefilter media 58. The outer liner 66 can be non-metal, such as plastic;alternatively, it may be metallic, such as expanded metal. As can beappreciated from observing the embodiment of FIG. 6, the outer liner 66circumscribes the filter media 58, and the filter media 58 circumscribesthe inner liner 64.

The filter element 14 is releasably sealed to the housing 12 at seal 68(FIG. 3). There are a variety of techniques for releasably sealing thefilter element 14 to the housing 12. In the embodiment shown, a radialseal 70 is formed between the element 14 and the housing 12.Specifically, an internally directed radial seal 70 is formed betweenthe first end cap 54 and the internal wall 46 of the housing body 16.

FIG. 8 shows an enlarged, cross-sectional of the first end cap 54. Thefirst end cap 54 has a sealing portion 72 extending into opening 74defined by the first end cap 54. In this embodiment, the sealing portion72 comprises a soft, compressible foam polyurethane constructed andarranged to radially compress when the element 14 is mounted over thewall 46. The compression of the sealing portion 72 against the wall 46forms the radial seal 70.

In accordance with principles of this disclosure, the cover 18 and thefilter element 14 are constructed and arranged to rotationally interferewith each other by engagement between an inside surface of the cover 18and an outer radial periphery of the filter element 14. This rotationalinterference with each other helps to inhibit internal rotation of thefilter element 14 within the housing 12. One way of accomplishing thisrotational interference is by having structure on the filter element 14that is non-circular. In the embodiment shown in FIGS. 4, 6, and 7, thesecond end cap 56 of the filter element 14 includes an outer wall 76circumscribing the tubular extension of filter media 58, and the outerwall 76 is non-circular. The outer wall 76 also forms an outer radialperiphery 78 of the filter element 14.

Preferably, the non-circular outer wall 76 defines at least one apex 80(FIG. 4). The at least one apex 80 cooperates with structure on thecover 18 to prevent the rotation of the element 14 within the housing12. In the embodiment shown in FIG. 4, the outer wall 76 has a pluralityof apices 80. The apices 80 can be irregularly spaced apart from eachother, or uniformly spaced from each other. Between each apex 80 is awall segment 82. The wall segments 82 can each be straight, to form apolygon shaped outer wall 76. Alternatively, the wall segments 82 can becurved. The wall segments 82 in the outer wall 76 can be a combinationof straight and curved. In the particular embodiment depicted, the outerwall 76 has evenly spaced apices 80 with straight wall segments 82therebetween to form a shape of a regular polygon.

The cover 18 has structure that cooperates with the outer radialperiphery 78 of the element 14 to result in rotational interferencebetween the cover 18 and the filter element 14. In the embodiment shown,the cover 18 has an inside surface 84 (FIG. 4 and FIG. 1) that engagesthe filter element outer radial periphery 78. The inside surface 84 willbe non-circular. In preferred embodiments, the inside surface 84 willhave at least one apex 86, and in the embodiment shown, has a pluralityof apices 86. In preferred embodiments, the inside surface 84 will havean engagement surface 88 shaped to mate with the outer radial periphery78. For example, while the outer radial periphery 78 is shown withoutwardly projecting apices 80, the engagement surface 88 will haveinwardly extending apices 86 to receive the outwardly extending apices80.

In the embodiment shown, the inside surface 84 is polygon-shaped;specifically, a shape of a regular polygon. As can be seen in FIG. 4,because of the shape of the outer radial periphery 78 of the element 14and the shape of the inside surface 84, each outwardly extending apex 80of the filter element 14 is received by an inwardly extending apex 86 ofthe inside surface 84 of the cover 18. This engagement traps the element14 relative to the cover 18 to prevent rotation of the cover 14 relativeto the cover 18. The cover 18 is secured to the body 16 with latches 28,so the cover 18 is prevented from rotating relative to the body 16. Assuch, the element 14 is prevented from rotating relative to the overallhousing 12, including both the body 16 and the cover 18.

In reference to FIGS. 6 and 7, in the embodiment shown, the outer wall76 of the second end cap 56 has a first section 90 and a second section92. The first section 90 corresponds to the outer radial periphery 78defining the non-circular shape that engages against the inside surface84 of the cover 18. The second section 92 extends from the first section90. In the embodiment shown, the first section 90 is immediatelyadjacent to the closed end 50, while the second section 92 extends fromthe first section 90 and is separated from the closed end 50 by thefirst section 90. In the embodiment shown in FIG. 7, the first section90 is pressed against the outer liner 66, while the second section 92 isspaced radially away from the outer liner 66 and the filter media 58.The second section 92 can have the same shape as the first section 90,or it can have the same shape as the filter media 58, such ascylindrical (a circular cross-section).

The second section 92 is part of a pre-cleaner for the air cleaner 10.Specifically, and in reference now to FIG. 3, the air cleaner 10 has adust ejector 94 as part of the housing 12; in particular, as part of thecover 18. Air to be filtered enters the housing 12 through the inlet 22,and the pre-cleaner 96 (FIG. 3) helps to separate out large dustparticles and eject them through the dust ejector 94 before they reachthe primary element 14. Specifically, the second section 92 of the outerwall 76 allows inlet air to circumferentially rotate or swirl around thesecond section 92. This rotation of the air around the second section 92creates centrifugal forces that cause dust particles to drop to thebottom 98 of the housing 12, where they flow through an ejector outlet100 in the cover 18 and then through an evacuation valve 102.

In reference again to FIG. 6, the second end cap 56 depicted includes anaxial portion 104 generally perpendicular to the outer wall 76. Theaxial portion 104 has a central region 106 with a closed recess 108projecting into the open filter interior 60. The closed recess extendsat least 30 mm, preferably 40-80 mm axially from the uppermost portion110 of the closed end 50. In the embodiment shown, the central region106 further includes a projection 112 extending axially from the centralregion 106. In the embodiment shown, the projection 112 extends at least10 mm, for example 12-30 mm from an innermost portion 114 of the closedrecess 108.

In the embodiment shown, the cover 18 includes structure to mate withthe second end cap 56 to help laterally support the filter element 14 inan operable position in the housing 12 with the radial seal 70 in place.In the embodiment shown in FIG. 3, the cover 18 includes a protrusion116 projecting into the closed recess 108 of the second end cap 56.Preferably, the cover 18 also defines a recess 118 oriented to receivethe projection 112 of the second end cap 56. As can be seen in FIG. 3,when the protrusion 116 is received within the closed recess 108, andwhen the projection 112 is received by the recess 118, this will helpkeep the filter element 14 in place mounted on the wall 46 with theradial seal 70 in place.

To install the filter element 14 into the housing 12, the filter element14 will be operably oriented into the housing body 16. This will includeforming the seal 68 between the element 14 and the housing 12. In theexample shown, radial seal 70 is formed by compressing the first end cap54 between and against the outer liner 66 and the wall 46 of thehousing. Next, the cover 18 is oriented over the element 14 and the openend 26 of the body 16. The step of orienting the cover 18 over theelement 14 and the housing body 16 includes engaging the cover insidesurface 84 and the filter element outer radial periphery 78 torotationally interfere with each other. For example, the second end cap56 of the filter element 14 has outer wall 76 with at least one apex 80.The at least one apex 80 is aligned with an oppositely oriented apex 86on the cover inside surface 84. In the example shown in FIG. 4, the stepof engaging the cover inside surface 84 and the filter element outerradial periphery 78 includes engaging a regular polygon shape on theouter wall 76 against a regular polygon shape on the cover insidesurface 84.

To service the air cleaner 10, the cover 18 is removed from the body 16by releasing the latches 28. The filter element 14 is then grasped andpulled through the open end 26 of the body 16. This releases the radialseal 70. The filter element 14 is then discarded. If a safety element 32is being used, removing the element 14 from the body 16 will expose thesafety element 32. If desired, the safety element 32 can also be removedfrom the body 16 and pulled through the open end 26 by releasing theradial seal 44. A new safety element 32 can then be installed byorienting it through the open end 26 of the body 16 and forming radialseal 44. Next, a new filter element 14 is provided and installed in thebody 16 by placing the open filter interior 60 over the safety element32 and then forming the radial seal 70 by compressing the first end cap54 sealing portion 72 against the housing wall 46 to form the radialseal 70. The filter element 14 is then rotationally locked relative tothe cover 18 by orienting the cover 18 over the element 14 and engagingthe outer radial periphery 78 relative to the inside surface 84 of thecover 18. The latches 28 are then engaged to secure the cover 18relative to the housing 12.

FIGS. 10-17 illustrate a second embodiment of an interface arrangementbetween a filter element 214 and a cover 218. Other than certainspecific structural differences, discussed below, the element 214 isstructurally identical as the described embodiment of element 14, andthe cover 218 is structurally identical to the cover 18.

In FIGS. 10-13, the filter element 214 is depicted as operably mountedwithin the cover 218. FIGS. 14 and 15 depict the filter element 214, andFIGS. 16 and 17 depict the cover 218.

As with the embodiment of FIGS. 1-9, the filter element 214 has an outerwall 276 that circumscribes a tubular extension of filter media 258(FIG. 11). Again, as with the embodiment of FIGS. 1-11, the outer wall276 defines at least one apex 280, and preferably, a plurality of apices280. In the embodiment of FIGS. 10-15, the outer wall 276 includes atleast one rib 300 projecting therefrom. In preferred embodiments, the atleast one rib 300 includes a plurality of ribs 300 projecting from theouter wall 276. In the preferred implementation illustrated in FIGS.10-15, the number of ribs 300 is fewer in number than the number ofapices 280. In the embodiment shown, each of the ribs 300 is alignedwith a respective one of the plurality of apices 280. In the preferredembodiment shown, every other apex 280 includes a rib 300 alignedtherewith. The purpose of the ribs 300 will be described further below.

In reference now to FIGS. 16 and 17, the cover 218 is illustrated. Thecover 218 has identical structure as the cover 18, with the exception ofventing slots 302. As with the embodiment of FIGS. 1-9, the cover 218has a cover inside surface 284, which is non-circular. The cover insidesurface 284, as with the embodiment of FIGS. 1-9, defines at least oneapex 286, and preferably, a plurality of apices 286. Each apex 286, inthe embodiment shown, is evenly spaced around the inside surface 284 ofthe cover 218. In the embodiment of FIGS. 10-17, the cover insidesurface 284 also defines at least one venting slot 302. In theembodiment shown, the at least one venting slot 302 is aligned with atleast one of the plurality of apices 286 in the cover inside surface284. Preferably, and in the embodiment shown, there are a plurality ofventing slots 302, with one respective venting slot 302 aligned with arespective one of the apices 286 in the cover inside surface 284.

In use, when the element 214 is assembled with the cover 218, theventing slots 302 help to allow air to escape or enter the volumebetween the element 214 and the cover 218 when installing or retrievingthe cover 218. Without the venting slots 302, air can get trappedbetween the cover 218 and element 214. Without the venting slots 302,when removing the surface cover 218 from the element 214, a vacuum couldbe created because the volume between the cover 218 and element 214 isonly slowly filled with air. The venting slots 302 allow air to escapeor enter the volume between the element 214 and cover 218.

In addition, at least some of the venting slots 302 operate to receivethe ribs 300 in the element 214. In the embodiment of FIGS. 1-9, withoutthe ribs 300, it can sometimes be possible to push the service cover 18onto the air cleaner over the element 14 into a closed position andengage the latches. This results in that the element 14 is mechanically“locked” in the service cover 18. When taking the service cover 18 off,the element 14 remains stuck in the cover 18 and is difficult to removefrom the cover 18. The ribs 300 at the element apices 280 prevent theelement 214 from being forced into place when its apices 280 aremisaligned with respect to the apices 286 of the cover 218. In theexample embodiment illustrated, ribs 300 are on every other apex 280 inorder to keep the venting function of the venting slots 302.

What is claimed is:
 1. A filter element comprising: (a) a tubularextension of filter media defining an open filter interior; (i) thetubular extension of media comprises a cylindrical extension of pleatedmedia; (b) a first end cap secured to the tubular extension of filtermedia; the first end cap having an opening in communication with theopen filter interior; the first end cap including a sealing portion; (i)the sealing portion extending radially into the opening and constructedand arranged to form a radial seal with a housing body, when the filterelement is operably installed in a housing body; (c) a second end capsecured to the tubular extension of filter media opposite of the firstend cap; the second end cap being a closed end cap with no openingstherethrough; (i) the second end cap including an outer wallcircumscribing the tubular extension of filter media; the outer wallbeing non-circular and including a plurality of first protrusionsradially projecting from the outer wall and a plurality of secondprotrusions radially projecting from the outer wall; the firstprotrusions projecting further from the outer wall than the secondprotrusions.
 2. A filter element according to claim 1 wherein the outerwall further includes a plurality of curved wall segments.
 3. A filterelement according to claim 1 wherein second protrusions include at leastone apex.
 4. A filter element according to claim 1 wherein the secondprotrusion comprise a plurality of apices.
 5. A filter element accordingto claim 4 wherein each of the second protrusions alternates with one ofthe first protrusions.
 6. A filter element according to claim 1 whereineach of the second protrusions alternates with one of the firstprotrusions.
 7. A filter element according to claim 1 wherein: (a) thefilter element further includes an inner liner and an outer liner withthe cylindrical extension of pleated media therebetween.
 8. An aircleaner assembly comprising a filter element according to claim 1; theair cleaner assembly including: (a) a housing body; (b) a separate coverremovable from the housing body; and (c) the filter element removablypositioned in the housing body with the sealing portion forming a radialseal with the housing body.
 9. An air cleaner assembly according toclaim 8 wherein: (a) the cover is mounted over the housing body and thefilter element; (b) the cover has an inside surface defining a pluralityof apices; and (c) the cover and the filter element rotationallyinterfere with each other by engagement between the cover inside surfaceand the filter element outer wall.
 10. An air cleaner assembly accordingto claim 9 wherein: (a) the cover inside surface defines at least oneventing slot aligned with at least one of the plurality of apices in thecover inside surface.